Large quantities of a number of man-made chemicals with the potential to disrupt the developing endocrine and nervous systems in wildlife and humans have been released into the environment. These chemicals are particularly damaging during the embryonic, fetal, and early postnatal periods because they resemble or interfere with the hormones, neurotransmitters, growth factors, and other signaling substances that normally control development. The effects are in many cases irreversible and often are expressed as changes in function rather than as obvious birth defects or clinical diseases. Functional changes pose challenges in documenting the extent of the lesion, especially in the case of neuroendocrinological damage. In the past decade, researchers have added new dimensions to their research strategies in order to compensate for these difficulties. The new approaches reveal more about the extent of the distribution of and exposure to chemicals that interfere with the endocrine and nervous systems and strengthen the links between exposure and damage in developing wildlife and humans. Based on this new knowledge, opportunities abound for extensive multi-disciplinary research involving developmental neurotoxicity.